1. Field of the Invention
The present invention relates to rolling ladders, and like devices. More particular, the present invention relates to an improved rolling platform stairway having a work platform supported at the upper end of a structural frame and a rolling base supported at the lower end of the frame, with a diagonally extending ladder communicating with the platform and with the base, and wherein an improved configuration of the frame allows the platform to be positioned above machines and other obstructions.
2. General Background
Rolling ladders and rolling stairways are commercially available. These devices typically include a structural frame made of welded or bolted tubular stock such as piping or of structural steel members such as angle shapes, flanged beams, channels and the like. One rolling platform ladder that is commercially available from the McMaster-Carr Supply Company of Atlanta, Ga. uses a rolling base having four casters, and an inclined stairway that has a number of treads or steps such as for example five to ten (5-10) steps.
Rolling platforms are available in a number of differing platform heights such as for example heights of between five and ten feet. Typically, rolling platform ladders include a structural frame that includes one or more vertical columns that are spaced away from the stairway portion and which limit movement of the device when approaching a vertically extending object. The vertically extending columns are positioned at the extreme end portion of the frame opposite the entry level tread. Because these support columns are vertical, they contact any object that is approached, limiting further movement of the apparatus. This prevents placement of the platform over objects such as conveyors, machines, and the like.
In an attempt to provide a rolling platform ladder that can straddle machines and obstructions, a Cantilever V-base ladder has been provided commercially to the industry. Cantilever V-base ladders include a ladder section that extends at an angle from the base and having an open portion under the top section of the ladder so that the ladder can straddle machines and obstructions. Cantilever ladders typically involve only a ladder section and do not provide a work area for the user at the top portion of the ladder.
Some rolling platform ladders provide stock piling shelves underneath the uppermost work platform. The shelves can be adjustable in some models.